|Keywords (Extracted from title, table of contents and abstract of thesis)
rodents, rice, wheat, sindh, , rodentia: muridae, bandicota bengalensis, millardia meltada, nesokia indica, tatera indica, mus sp, oryza sativa, triticum aestivium, cenchrus biflorus, cynodon dactyl on, cyperus glomeratus, desmostachya bipinnata, eleocharis sp., ipomoea aquatica, paspalidium geminatum, paspalidium distichum, scirpus litoralis, bandicota bengalensis
No country is free from the depredation of vertebrate pests especially by rodents, which in many cases cause severe economic losses. It has been estimated that one fifth of the food stuff planted every year in the world are never eaten by people because of the damage by rodents. At present most of the efforts for controlling these pests in our cultivations are being made in the absence of adequate knowledge on their feeding patterns. Scientific study of food habits is essential to an intelligent understanding of our agricultural pests. Knowledge of food used by specific animal is basis for the management of their population and environment.
This thesis is based on the results of the identification of 1,404 stomach contents of rodents (Rodentia: Muridae) which includes Bandicota bengalensis, Millardia meltada, Nesokia indica, Tatera indica and Mus sp collected over three years (2003-2005) from rice and wheat fields of different districts of Sindh, Pakistan. The plant and animal materials were identified and the percent relative frequency of individual food item was calculated.
Out of 32 different species of plants collected from rice and wheat fields of Sindh, only II species (Oryza sativa, Triticum aestivium, Cenchrus biflorus, Cynodon dactyl on, Cyperus glomeratus, Desmostachya bipinnata, Eleocharis sp., Ipomoea aquatica, Paspalidium geminatum, Paspalidium distichum, Scirpus litoralis) were identified in 389 stomachs of Bandicota bengalensis, 13 species (Oryza sativa, Triticum aestivium, Desmostachya bipinnata, Cyperus glomeratus, Ipomoea aquatica, Eleocharis sp., Paspalidium geminatum, Cynodon dactylon, Phyla nudiflora, Scirpus maritimus, Bramia monnerii, Cenchrus biflorus, Chlorus barbata ) were detected in 621 stomachs of Millardia meltada, 8 species (Oryza sativa, Triticum aestivium, Chlorus barbata, Cyperus glomeratus. Bramia monnerii, Scirpus maritimus, Phyla nudiflora, Ipomoea aquatica) were found in 254 stomachs of Mw; sp, 7 (Oryza sativa, Triticum aestivium, Scirpus maritimus, Cynodon dactylon, Cyperus glomeratus, Ipomoea aquatica, Paspalidium geminatum) were found in 101 stomachs of Nesokia indica and 5 (Oryza sativa, Triticum aestivium, Scirpus maritimus, Ipomoea aquatica, Phyla nudiflora) were identified from 39 stomachs of Tatera indica. From all rodent stomachs. 16 different species of plants plus insects material were identified.
Dominant food items in the diet of the mentioned rodent species were identified. It has also been observed that Bandicota bengalensis and Millardia meltada had great dependence on rice and wheat among the five rodent species. Mus sp has also dependence up to some extent but exploits other food too, while Nesokia indica seems to have great change in its feeding behavior at harvest time. Before that it spends most of its time underground eating tubers of Scirplls maritimlls but feeds above the ground on the crops at the time of harvest.
Data on abundance and reproduction has also been gathered. It has been observed that changes in abundance generally correspond to change in reproduction. The timing of abundance and reproduction of rats coincides with an increase in the amount of grain eaten by rats. Breeding peaks correspond with the maturity of the agricultural crops. It has also been noted that reproductive pattern was sharply bimodal and matched very closely with two crop cycles (rice and wheat) in a year.
Damage indices have also been calculated in identifying the most important pest species and the time when most damage occurs. A comparison of the damage indices has been made between rice and wheat fields of Central Punjab and Sindh. Overall percentages of damage index were high in Sindh as compared to Central Punjab and severe damage was caused by Millardia meltada, Bandicota bengalensis and Mus sp.
Agricultural practices that may reduce rodent populations are identified and suggestions for the timing of rodenticide application are given. Suggestions regarding the use of particular taste additives in bait have also been specified to make the bait formulation more effective for control of field rats.